This invention relates to an apparatus for controlling the idling rate (engine rotation speed) of an engine and, more particularly to an apparatus, which can prevent variations of the idling rate of the engine when driving a generator for charging a battery with the engine.
In a prior art engine idling control apparatus, the idling rate of the engine is held at a desired idling rate through control of the supply rate of intake air to the engine according to the difference between the desired idling rate and the actual idling rate of the engine.
In using the prior art apparatus noted above in cases where an electric load (such as a headlight and a motor-driven radiator and fan) is greatly consuming electric power, the operation of the generator which supplies power to the electric load increases the engine load to reduce the rotation speed or idling rate of the engine. When the idling rate of the engine is reduced, the desired idling rate is eventually produced by the above control operation. However, depending on the magnitude of the electric load, an engine stall is liable to result because of slow control response.
Accordingly, it has been proposed to correct the rate of in-take air supply by detecting a plurality of electric load switches as disclosed, for instance, in Japanese Patent Disclosure 58-197449. In this case, however, switches and input circuits corresponding in number to the number of electric loads are necessary, thus increasing the scale and complicating the construction of the control apparatus.